Circuit breakers



March 26, 1963 D. H. HOLDT 3,083,281

CIRCUIT BREAKERS Filed June 22. 1960 4 Sheets-Sheet 1 INVENTOR oa/v/uo ILL/1,0407;

BY 953M B i M ATTORNEYS March 26, 1963 D. H. HOLDT 3,083,281

CIRCUIT BREAKERS Filed June 22. 1960 4 Sheets-Sheet 2 INVENTOE 'gw g mknlnu ATTORNEYS March 26, 1963 D. H. HOLDT 3, 1

CIRCUIT BREAKERS Filed June 22. 1960 4 Sheets-Sheet 3 INVENTOR OO/VflLD h. 170407;

March 26, 1963' D. H. HOLDT 3, 8

CIRCUIT BREAKERS Filed June 22. 1960 4 Sheets-Sheet 4 ATTORNEYS removed;

United States Patent 3,083,281 CIRCUIT BREAKERS Donald H. Holdt, Cambridge, Md., assignor to Airpax Electronics Incorporated, Fort Lauderdale, F151;, a corporation of Maryland Filed June 22, 1960, Ser. No. 37,942 16 Claims. (Cl. 200-106) This invention relates to circuit breakers, more particu larly to circuit breakers of the type provided with means for manually operating the circuit-controlling contacts between open and closed positionstogether with automatic tripping means for causing thecontacts to move to open circuit position uponthe occurrence of a predetermined amount of circuit current overload.

It is an object of the invention to provide an improved shockproof circuit breaker having a trip device that is simple, efficient, positive and reliable in operation.

A further object is to provide a'circuit breaker that is light, compact, durable, safe and simple to use and sealed within a dustproof casing particularly adapted for use on vehicles, such as airplanes, truck-s, etc.

A further object is to provide a circuit breaker wherein the manual control element for opening and closing the circuit-controlling contacts, when used as an ordinary switch, also functions to set the device for automatic operation under overload conditions.

A further object is to provide a circuit breaker employing a floating toggle linkage.

A further object is to provide a circuit breaker comprised largely of simple sheet metal stampings and readily available materials thereby rendering it easy and inexpensive to manufacture.

The invention itself, however, both as to structure and operation, together with the objects and advantages thereof, will best be understood from the following detailed description of a specific embodiment thereof when read in connection with the accompanying drawings, in which:

FIGURE 1 is in part a vertical sectional .view taken on line I.I in FIGURE 3 but with the casing in section mounted on the device showing the circuit breaker mecha nism in open position; I

FIGURE 2 is a viewlike FIGURE 1 but with the circuit breaker mechanism in closed position;

FIGURE 3 is an endelevational view of the device viewed from the left in FIGURE 1 with the casing removed;

, FIGURE 4 is an end elevational view of the device viewed from the right in FIGURE 2 with the casing FIGURE 5 is a fragmentary view in side elevation showing thepositioning of the toggle linkage during movement of the circuit closing contacts when moved from open to closed'position; l g 1.. 1. FIGURE 6 is a section taken on line VI- -VI in FIG- URE 1 showing the compound armature structure;

- FIGURE 7 is a perspective view of the compound armature structure;

FIGURE 8 is a diagram-of forces acting on the toggle linkage mechanism;

; ,FIGURE 9 is a schematic showing of the electrical connections of the circuit breaker; 1

FIGURE lO is' a side elevational View of the main armature. A k i p a 1 Referring to the drawings, the supporting frame comprises a support plate 1 and a side wall 2 depending therefrom, both formed from' a single metal stamping. Fastened integrally as by welding to the side wall 2 at the bottom isfa bifurcated 'terminalfplate 3', each bifurcation of which carries a terminal 9 providing; means to connect the structure to the circuit to be controlled. Each termi- "Ice nal 9 is insulated from the terminal plate 3 by means of glass insulation 10' or the like in a mounting'b'ushing 10, as shown in FIGURE 1.

On the top of support plate 1 is rigidlymounted atoggle bushing 4 in which toggle handle or lever 6 is pivotally mounted intermediate its ends at 7 and extends down through support plate 1. A rubber diaphragm 01' seal 8 closes the opening aroundthehandle 6 and as shown is bonded to "both the handle 6 and'bushing 4. The bushing 4 is shown threaded at 5 providing a mountin; means for the circuit breaker structure. I

As shown in FIGURES 1 and 2', a solenoid I1 suitably connected electrically to terminals 9 is mounted 'below plate 1 by means of depending members, or equivalent means 12 rigidly secured to the support plate 1. 'A compound armature structure A (FIGURE 7)'iis pivotally' mounted, in operative relation to pole piece 13 of the solenoid, on shaft 14 supported at its'ends by support side plate 2 and a laterally extending Wing member 15 from the plate 2. As shown particularly in FIGURES-6 and 7, the compound armature A comprises-impart an auxiliary armature 16 pivotally mounted on shaft 14'and having its upper end opera'bly aligned-with thesolenoid pole piece 13. The auxiliary armature 16 in its. lower part is bifurcated, the legs 17 and 18 thereof being of considerable length and of a sizeto balance the armature about shaft 14. Auxiliary armature16 is limited in its counter-clockwise movement relative to the pole piece 13 (FIGURE 1) by means of a fixed stop 19 on -a bracket 43 depending from aportion of backwall 2: (FIGURE 1). A whisker-type spring 20 is solder-anchored on plate wing extensionlS (FIGURE 1) andextendsaroundthe lower edge thereof and bears against the side of auxiliary armature 16 to constantly bias it anticlockwise whereby its leg 17 is normally held against stop 19 (FIGURES -1 and 2) when the solenoid is'de-energized.

The main armature component 21- also'pivotally mounted on shaft 14 and in juxtaposition .to. the auxiliary armature 16. A spring 40 around shaft 14 urges it counterclockwise inFIGURESIl and 7. Thisrnovement is limited by a side arm' extension 21f on armature 21 engaging stop 42 on bracket ,41 depending from frame wing 15., Stop abutments1'9 and 42 are so adjusted that the upper end of main arma'turej 21 isfslightly lang-ularly spaced relative to auxiliary armature 16 when the circuit and no overload condition obtains. The lower-"end of main armature 21 comprises a latch abutment 22' disposed medially of legs 17 and 18 for a purpose tojbe later described.

On a fixed pivot shaft '23 carried by the back wall 2 of the frame is mounted a relatively stiff but. resiliently bend-able lever 24.intermediateits length, At'its end remote from the armature it is pivotally connected at 25 to ,a bifurcated toggle link 26 Ush aped atits upper end while.atJitstfreeother end it carries va suitably insulated circuit closingcontact 27 Immediately above lever 24 and pivotally monnted onthe same fixed pivot shaft 23 is latch lever 28 of relatively rigid construction likewise carrying. suitably insulatedjcircuitclosing contact 29 which is positioned so as to be engageablefwith contact27 on lever 24. Theend of latch lever 28 remote frornthe ,arm'atureis bent toform a stop abutment finger 30 'disposed betweenthe bi-furcations of toggle link 2 6 and engageable with a pin 31 carriedby the bifurcations of link 26 at a point closely adjacent mounting shaft 25. The finger 30 and-pin3 1 when engagedllirr it the angular opening of latch lever 23 and arm"24 about their common pivot 23. The other free end of'latch lever 28 is bent to form a latch member 32 adapted, under..oonditions to beexplained, to engage thelatching .abutment'ZZ Iof main armature .21. A coiledispring 23' surrounds shaft 23 and has ends. which bear respectively against 3 levers 24 and28 to normally urge the circuitclosing contacts 27 and 29 thereon apart into open circuit position.

The end of bifurcated toggle link 26, above and opposite'its end pivoted at 25,'is pivotally connected to the lower end of toggle handle 6 by'means of a pivot pin 33. Also pivotally mounted on and carried by pin 33 and nested between the arms of the U-shaped portion oflink 2 6 'is a metallic spring guide and abutmentrnember 34 which has an oliset guide arm 34 extending therefrom and slidablyengaging in a guide and aligning aperture 36 in anon-metallic springguiding and mounting member 35 pivotally mounted at 37' at a fixedpoint on frame wall 2. Mounted between and carried by members 34 and 35 is altoggle actuating compression spring 38 which con- 'stantlytends to bias member 34, as well as the ends of {members-6 and 26*also pivotally attached to pin 33, away from member35 andits fixed pivot shaft 37. The guide member 34 maintains the spring support members 34 and 35in :proper alignment at all times. To limit the distance that spring support member 34 may move under the "action'of spring 38 an abutment 39 is provided on lfrainewing in alignment with the path o-fmovement of spring support 34, the latter having a suitable abutment surface forengagement with abutment 39.

Ajsuitable thin metallic casing '45, of rectangular shape,

iln the particular embodiment illustrated, compactly encloses the circuit breaker mechanism mounted below supportplate '1 and is apertured .at its bottom to snugly fit in sealing relation around the terminal bushings 10. The

upper edge or opening'of the casing closely engages the periphery of support plate 1 land is sweat-soldered thereto in-sealing relation. The casing 45, together with'the seal "8'Taroundthetoggle handle 6, thus seals the circuit breaker mechanis'm"against'the admission of dust andmoisture n We flfl v The combinedcircuit breaker and switch operates as "follows:

7 With the parts in the jposition in FIGURE 1, and the cont-acts 27,-29in open'position, the toggle handle 6 is manually swung eoun'ter-clockwise to the position shown 'inFIGURE-Z such movement pivot pin 33, and thespri'ng abutment 34 and upper'e'nd of toggle link26 'piwotally connected thereto, are moved to the right compressing toggle spring 38. As link 26, which is actually floating, in view of itsmounting at both ends on movable pivots, thusjmovedQits lower end, through its pivotal attachment jwith'1ever'24'*at 25, is forced downwardly.

n The initial downward movement" causes clockwise movef nientof lever24ab'out its fixedpivot 23, causing spring 23"fo yieldingl'y urgelat'ch lever 28 clockwise about its common pivot 23 such that its latch end 32 engages the Iatchfmember'ZZ of themain armature 16 whichis in its pathga j indicated in'FIGURES 2 and s.

. idhghout the" movement of parts thus far described in 'l'the o era-brief the dev ce toggle-pivot as 'lies to the left bt a'straight lineextending betweenhandle'pivot 7 and toggle," may 25. Since men "lever 28 cannot move upany further, due to its latchend 3 2 abuttt'ing latch fabutment22 of the main armature 21 due "to the u ward pressure of contact 27 on Contact 29 and it being mounted near its other end on fixed pivot'23,continu ed movement of handle 6, towardtheFIGURE 2 position forces toggle :link 26 fur'ther downward. This downward movement 'pushespivot pin" 25 further downward causing a downflexure and deflection "of the right hand end 24" of 'lever24 lying between pivots ,23 and 25 while a slight and contact 29. The downward deflection of the end 24 of lever 24 is at a maximum when toggle pivot pin 33 is at dead center, that is, lines in the straight line passing through pivots 7 and 25,asindicated at 33' in FIGURE 5. The final movement of handle 6to the FIGURE 2 position swingstogglepivot pin 33Ipast dead center to the cocked position'indicat'ed at 33" in FIGURE 5. As this occurs the deflected end of the lever flexes upwardly by the force thusstored in it to substantially the straight line position shown in FIGURE 2 thereby exerting sulficient force, by its inherent resistance to flexure, against the end of the floating toggle linkage formedby the lower end of handle 6 and toggle link 26, to hold it in its cocked (over dead center) position. It will be noted that while spring 38 is highly compressed at this time, its force acting on toggle link 26 is of a very small value by reason of the fact, as clearly apparent in FIGURES 2. and 5, that the greater component o-f-its fiorce is directed up through handle pivot 7, the toggle link .pivot 33 beingdisposed just slightly out of and'to-the left of a straight line passing through handle pivot 7 andfixed spring abutment pivot 37. Thus the contacts 27,-29 are held in engagement by the floating toggle just described so long as the latch end 22 of the main armature 16 is held in engagement with end32-of latch lever 28. 6

Assuming the circuit breaker device is'connected atits terminals 9, 9 into a circuit it is adapted to control, if.

the current only slightly exceeds a percent load, the electromagnetic force in'solenoid 11 will only exert sufiicient force on auxiliary armature '16 to move it clockwise (FIGURE 1) into contact with the upper'end of main-armature 21 without releasing the latch abutment 22 out of-tl1e path oflatch member 32 on the adjacent endof latch lever 28.

However, in the event of a predetermined overload This slight clockwise out of engagement with latch finger 32 onlatch lever 28. Coil springs '23 'then immediately acts to spread latch lever;28 and arm map'arr about their fixed pivot shaft.23,releasing toggle abutment means 24, 25, thereby permitting the small but effective component of f'orce of toggle spring 38 to move pin 33 to the left FIG- URE 2). Immediately the full force of toggle spring 38 becomesefiective to thrust and yieldingly hold the toggle handle 6 and toggle link 26 to the fully released position shown in FIGURE 1 until the mechanism is again manual- "ly operated asabove-described to again close contacts 27,

The circuit breaker may obviously be used as a con}, ventional manually operable switch; When it is-so used the circuit is closedat 27, 29 in-exactly the same way as previously described by oscillating handle 6 from the position in FIGURE I1 to that shown in FIGURE 2' when used as "a circuit breaker. -All components will then be dis- "position. Frorn the previous description 'it'is apparent 1 that with latch lever 28 and arm 24 b'oth'being initially latched and held in the position shown in FIGURE 2 the manual oscillation 6f handle 6 tothe'FIGURE lposition swings toggle pin- 33*to'the left in' FIGURE 1 fore ing the toggle link downwardly to depress or deflect the "right-hand end24' of arm 24 while toggle pin 33 passes 7 through dead center,"as happenedwhen the contacts were manually closed,'as previously described relative to circuit breaker use. The toggle spring 38 then obviously assists in them'ovement of the handle to' the fully open contact position. It is thus obvious that the circuit can be manually opened or closed through the device at 27, 29 regardless of the degree of excitation of solenoid 11 or even when no current flows therethrough.

While the invention has been shown and described in accordance with the patent statutes, it is to be understood that various changes in the details of the structure may be made without departing from the spirit of the inven- 7 tion. It is desired therefore that the invention be limited only by the scope of the appended claims.

What is claimed is:

1. In an automatic overload circuit breaker comprising in combination, a supporting frame having mounted thereon a manual actuating member, dual lever means pivotally mounted intermediate their ends at a point on said supporting frame spaced from said actuating member, circuit-controlling contact means carried solely on said dual lever means, an electromagnetic device electrically interconnected with said contact means and including armature means, linkage means pivotally connecting one end of one of said dual lever means and said manual actuating member and forming therewith a floating toggle linkage, the other of said dual lever means comprising a latch means for said floating toggle linkage and having thereon a latch device operably associated with latch means on said armature means, an actuating spring means operably connected with said floating toggle linkage intermediate its ends and so mounted as to move said toggle linkage when unlatched to cause opening of said circuit closing means when the electromagnetic means under predetermined overload conditions actuates said armature means to release the said latch device on said other dual lever.

2. An automatic overload circuit breaker comprising in combination a supporting frame, a manually actuated lever pivoted intermediate its ends on said frame, a second lever, means pivoting said second lever intermediate its ends on said frame at a point spaced from said first mentioned lever, link means pivotally connecting one end of each of said first and second levers therebyforming a floating toggle linkage, spring means effecting movement of said toggle linkage, a third lever forming a latch means pivoted intermediate its ends on the said means pivotally. mounting said second lever, one end of said third lever forming a latch means, circuit closing contact means mounted on said pivoted second and third levers, a solenoid and pivoted armature means therefor mounted on said frame, said armature having a latch element thereon operable to be engaged by the said latch element on said third lever, said third lever and armature latch elements operable together to hold the floating toggle linkage stationary against the action of the spring means when manually moved in one direction over dead center, the solenoid being responsive to circuit overload conditions to release the floating toggle linkage whereby the spring means moves the toggle linkage and circuit contacts to open position.

3. In a device of the character described, a support structure, manual actuating lever means pivoted intermediate its length thereon, fixed pivot means on said support structure and spaced from said actuating lever means, two lever means mounted on said fixed pivot means and disposed substantially normal to said manual actuating lever means, spring means acting between said two lever means tending to move said lever means angularly apart, a bifurcated link pivotally connected at its ends to one end each of the manual actuating lever and one of said two lever means thereby forming a floating toggle linkage, the second of said two lever means having an end lying between the bifurcations of said link, pin means on said link coasting with said lever end to limit its arcuate movement in one direction, a latch finger on the other end of said second other lever means, a circuit closing and opening contact mounted on said second other lever intermediate its end latch finger and pivotal mounting, a coacting circuit contact mounted on the free end of said one of the two lever means, a pivoted latch means on said support structure, said latch being operable to engage the latch finger on the end of said second other lever, spring means urging said latch into the path of said latch finger, spring means positioned to constantly exert an actuating force through the pivotal connection of said link and manually operating member, said latch and said two levers in cooperation with the circuit contacts carried thereby when engaged holding the floating toggle linkage over dead center against the action of said toggle spring means, the manual actuating member being operable to move the floating toggle linkage against the holding action of the latch and two lever means to a position back over dead center whereby the full force of the toggle spring is effective to complete the cont-act opening movement.

4. In a device as claimed in claim 3 including electromagnetic means'and an armature therefor, said armature comprising said pivoted latch means.

5. The device as defined in claim 3 including motor means, said pivoted latch means comprising a part of said motor means.

6. A circuit breaker comprising a mounting frame, a manually operable first lever pivoted intermediate its length on said frame, a second lever pivotally mounted intermediate its length on said frame in spaced relation to said manually operable lever, a link pivotally connected by means of pin means to an end of said second lever, said first lever and said second lever and link forming a floating toggle linkage, the said second lever being operably associated with releasable latching means whereby said second lever may be held in a fixed position, toggle actuating spring means mounted on the frame to thrust against said toggle linkage, said spring means moving said floating toggle linkage through a dead center position when the latching means operably associated with the said second lever is released.

7. The circuit breaker defined in claim 6 wherein circuit controlling contact means are carried by said second lever means and said releasable latch lever means, motor means mounted on said frame, said motor means being electrically connected to said contacts and operable under overload conditions in an electric circuit controlled thereby to release said latching means and cause said toggle spring through said floating toggle linkage to open said electric circuit.

8. The device as recited in claim 6 wherein the pin means connecting said manually operable first lever and said link pivotally carries a first spring abutment member, a second spring abutment member pivotally mounted on said frame, an offset guide arm on said first spring abutment member engaging an aperture in said second spring abutment member to maintain said abutment members in alignment with each other, the toggle actuating spring being mounted on said abutment members.

9. The device as recited in claim 8 wherein the said link is U-shaped at its end adjacent its pivotal connection to said manually operable lever means, said spring abutmentmeans carried by said toggle pin means pivotally connecting said manual lever and said link being disposed between the arms of said U-shaped end of said link.

10. The structure as defined in claim 6 wherein circuit controlling contact means are carried by said second lever means and said latching means, electromagnetic means mounted on said frame being electrically connected to said contacts and operable under overload conditions in a circuit controlled thereby torelease said latching means and cause said toggle spring through said floating toggle to open said circuit.

11. The structure as defined in claim 10 wherein said latching means comprises a rigid lever pivotally mounted on the means pivotally mounting said second lever, and spring means interposed between said rigid lever and said second lever means, said last-named spring means releasing said toggle means for actuation by said toggle spring when said rigid. lever is released by said electromagnetic means.

12. The structure as defined in claim 11 wherein an end of said rigid lever forms a limit stop means in association with pin meanson said link operative to limit opening movement of said rigid lever under the action of said last-named spring means.

13. The device as defined in claim 12 including abutmerit means on said frame structure engageable by spring abutment means on said toggle linkage to limit its movement in one direction under the action of said toggle spring.

14. In a circuit breakerhaving relatively movably mounted lever means carrying co-acting contact means for opening and closing aneleotric circuit, manual means to actuate said relatively movably mounted contact means, latch means to hold said contact means closed, motor means in said electric circuit effective to release said latch mean-s on occurrence of predetermined circuit overload, the combination therewith of a floating toggle linkage connecting said manually aetuabile means and one of said movably mounted contact means, spring means acting through the pointof connection of said floating toggle linkage with said manual means to cause said floating toggle [linkage to open said movably mounted contact means when said latch means is released by said motor means.

15. A circuit breaker comprising a frame means, a manually operable first lever pivoted intermediate its length on, said frame means, means pivotally mounting a slightly resilient second lever intermediate its length on said frame means in spaced relation to said manually operable lever, electrical contact means mounted at one end on said second lever, a link, means p-ivotally connecting .said link to the opposite end of said second lever and the adjacent end of said first lever, said first lever and said second lever and link forming a floating toggle linkage, a rigid'latch lever pivotedintermediate-its length on said, pivotal means in overlying relation to said second lever and with one of its, ends lying adjacent said link, electrical contact means mounted, intermediate the length of said latch lever in cooperative relation to said. first mentioned electrical contact means, spring meansbiasing said second lever-and latch lever toward cont-act open position, abutment means movable to. engage the opposite end of said latch lever, said second lever, when acted upon by said first lever means in opposition to said. spring means to engage said contacts while said movable abutment means is engaged with said opposite end'of said latch lever, being deflected out of alignment atits said opposite end as the toggle link-age passes through its dead center position by the operation of said first lever to hold said contacts in engagement with each other.

16. The circuit breaker as defined in claim 15 further including spring means mounted to exent a force on said toggle linkage connection of said first lever with said link tending to open said contacts when held closed by the said deflection of said second lever, motor means connected in an electrical circuit including said electrical contact means, said motor means operable on a predeter-v mined overload to actuate said movable abutment means out of engagement with said opposite end of said latch lever to thereby release said toggle linkage and cause movement ofsaidcontaot means to open position by said toggle spring means.

References Cited in the file, of this patent UNITED STATES PATENTSv 2,107,246 Jackson Feb. 1,1938

2,182,773 Sachs Dec. 5,1939

2,473,848 Baxter June 21, 1949 2,690,486v Wilckens ..r l Sept. 28, 1954 2,692,925, Schindler "7... Oct. 26, 1954 FOREIGN PATENTS 794,740 France Feb. 24-, 1936 

1. IN AN AUTOMATIC OVERLOAD CIRCUIT BREAKER COMPRISING IN COMBINATION, A SUPPORTING FRAME HAVING MOUNTED THEREON A MANUAL ACTUATING MEMBER, DUAL LEVER MEANS PIVOTALLY MOUNTED INTERMEDIATE THEIR ENDS AT A POINT ON SAID SUPPORTING FRAME SPACED FROM SAID ACTUATING MEMBER, CIRCUIT-CONTROLLING CONTACT MEANS CARRIED SOLELY ON SAID DUAL LEVER MEANS, AN ELECTROMAGNETIC DEVICE ELECTRICALLY INTERCONNECTED WITH SAID CONTACT MEANS AND INCLUDING ARMATURE MEANS, LINKAGE MEANS PIVOTALLY CONNECTING ONE END OF ONE OF SAID DUAL LEVER MEANS AND SAID MANUAL ACTUATING MEMBER AND FORMING THEREWITH A FLOATING TOGGLE LINKAGE, THE OTHER OF SAID DUAL LEVER MEANS COMPRISING A LATCH MEANS FOR SAID FLOATING TOGGLE LINKAGE AND HAVING THEREON A LATCH DEVICE OPERABLY ASSOCIATED WITH LATCH MEANS ON SAID ARMATURE MEANS, AN ACTUATING SPRING MEANS OPERABLY CONNECTED WITH SAID FLOATING TOGGLE LINKAGE INTERMEDIATE ITS ENDS AND SO MOUNTED AS TO MOVE SAID TOGGLE LINKAGE WHEN UNLATCHED TO CAUSE OPENING OF SAID CIRCUIT CLOSING MEANS WHEN THE ELECTROMAGNETIC MEANS UNDER PREDETERMINED OVERLOAD CONDITIONS ACTUATES SAID ARMATURE MEANS TO RELEASE THE SAID LATCH DEVICE ON SAID OTHER DUAL LEVER. 